The communications industry is rapidly changing to adjust to emerging technologies and ever increasing customer demand. This customer demand for new applications and increased performance of existing applications is driving communications network and system providers to employ networks and systems having greater speed and capacity (e.g., greater bandwidth). In trying to achieve these goals, a common approach taken by many communications providers is to use packet switching technology.
A multistage packet switching device uses multiple forwarding table lookup operations to determine how to forward a packet through, and from, the packet switching device. For example, a packet is received on an ingress line card. A first lookup operation is performed in an ingress forwarding table thereon to determine an egress line card to which the packet is then forwarded. A lookup operation is then performed in an egress lookup table on the egress line card to identify from which interface of the egress line card to forward the packet.